SpringBoot2：web开辟常用功能实现及原明白析-上传与下载 - ToB企服应用市场:ToB评测及商务社交产业平台

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestPart;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import java.io.File;
import java.io.IOException;
/**
* 文件上传测试
*/
@Slf4j
@RestController
public class FileTestController {
/**
* MultipartFile 自动封装上传过来的文件
* @param headerImg
* @param photos
* @return
*/
@PostMapping("/upload")
public String upload(
@RequestPart("headerImg") MultipartFile headerImg,
@RequestPart("photos") MultipartFile[] photos) throws IOException {
log.info("上传的信息：headerImg={}，photos={}",
headerImg.getSize(),photos.length);
if(!headerImg.isEmpty()){
//保存到文件服务器，OSS服务器
String originalFilename = headerImg.getOriginalFilename();
headerImg.transferTo(new File("E:\\workspace\\boot-05-web-01\\headerImg\"+originalFilename));
}
if(photos.length > 0){
for (MultipartFile photo : photos) {
if(!photo.isEmpty()){
String originalFilename = photo.getOriginalFilename();
photo.transferTo(new File("E:\\workspace\\boot-05-web-01\\photos\"+originalFilename));
}
}
}
return "OK";
}
}

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spring:
servlet:
multipart:
max-file-size: 10MB 单个文件最大值
max-request-size: 100MB 单次请求上传文件最大值
file-size-threshold: 4KB 内存中IO流，满4KB就开始写入磁盘

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import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
@Configuration
public class RestTemplateConfig {
@Bean
public RestTemplate restTemplate(){
return new RestTemplate();
}
}

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@PostMapping("/upload")
public String upload(
@RequestPart("headerImg") MultipartFile headerImg,
@RequestPart("photos") MultipartFile[] photos) throws IOException {
log.info("上传的信息：headerImg={}，photos={}",
headerImg.getSize(),photos.length);
String url="http://127.0.0.1:8080//upload2";
//封装请求头
HttpHeaders httpHeaders = new HttpHeaders();
httpHeaders.set("Content-Type", MediaType.MULTIPART_FORM_DATA_VALUE + ";charset=UTF-8");
httpHeaders.set("test1", "1");
httpHeaders.set("test2", "2");
MultiValueMap<String, Object> form = new LinkedMultiValueMap<>();
//文件处理
FileSystemResource headerImgFile = new FileSystemResource(multipartFile2File(headerImg));
form.add("headerImg", headerImgFile);
FileSystemResource[] photosArr = new FileSystemResource[photos.length];
for (int i = 0; i < photos.length; i++) {
photosArr[i] = new FileSystemResource(multipartFile2File(photos[i]));
form.add("photos", photosArr[i]);
}
HttpEntity<MultiValueMap<String, Object>> files = new HttpEntity<>(form, httpHeaders);
RestTemplate restTemplate = new RestTemplate();
//发送请求
String result = restTemplate.postForObject(url, files,String.class);
return result;
}
private static File multipartFile2File(@NonNull MultipartFile multipartFile) {
// 获取文件名
String fileName = multipartFile.getOriginalFilename();
// 获取文件前缀
String prefix = fileName.substring(0, fileName.lastIndexOf("."));
//获取文件后缀
String suffix = fileName.substring(fileName.lastIndexOf("."));
try {
//生成临时文件
//文件名字必须大于3，否则报错
File file = File.createTempFile(prefix, suffix);
//将原文件转换成新建的临时文件
multipartFile.transferTo(file);
file.deleteOnExit();
return file;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}

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@PostMapping("/upload2")
public String upload2(
@RequestPart("headerImg") MultipartFile headerImg,
@RequestPart("photos") MultipartFile[] photos) throws IOException {
if(!headerImg.isEmpty()){
//保存到文件服务器，OSS服务器
String originalFilename = headerImg.getOriginalFilename();
headerImg.transferTo(new File("E:\\workspace\\boot-05-web-01\\headerImg\"+originalFilename));
}
if(photos.length > 0){
for (MultipartFile photo : photos) {
if(!photo.isEmpty()){
String originalFilename = photo.getOriginalFilename();
photo.transferTo(new File("E:\\workspace\\boot-05-web-01\\photos\"+originalFilename));
}
}
}
return "upload2 OK";
}

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import org.springframework.core.io.Resource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
@Slf4j
@RestController
public class FileTestController {
private static final String FILE_DIRECTORY = "E:\\workspace\\boot-05-web-01\\photos";
@GetMapping("/files/{fileName:.+}")
public ResponseEntity<Resource> downloadFile(@PathVariable String fileName) throws IOException {
Path filePath = Paths.get(FILE_DIRECTORY).resolve(fileName).normalize();
Resource resource = new FileUrlResource(String.valueOf(filePath));
if (!resource.exists()) {
throw new FileNotFoundException("File not found " + fileName);
}
// 设置下载文件的响应头
HttpHeaders headers = new HttpHeaders();
headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename="" + fileName + """);
return ResponseEntity.ok()
.headers(headers)
.body(resource);
}
}

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@GetMapping("/downloadNetFileToLocal")
public Object downloadNetFileToLocal(@RequestParam("url") String fileUrl) throws Exception {
JSONObject result = new JSONObject();
String fileName = fileUrl.split("/")[fileUrl.split("/").length-1];
URL url = new URL(fileUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(5000);
InputStream inputStream = connection.getInputStream();
FileOutputStream fileOutputStream = new FileOutputStream("E:\\workspace\\boot-05-web-01\\photos\"+fileName);
byte[] buffer = new byte[1024];
int byteread;
int bytesum = 0;
while ((byteread = inputStream.read(buffer)) != -1){
bytesum += byteread;
fileOutputStream.write(buffer,0,byteread);
}
fileOutputStream.close();
result.put("bytes",bytesum);
result.put("code",200);
return result.toString();
}

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@GetMapping("/downloadNetFile")
public ResponseEntity<?> downloadNetFile(@RequestParam("url") String fileUrl) throws Exception {
String fileName = fileUrl.split("/")[fileUrl.split("/").length-1];
URL url = new URL(fileUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(5000);
InputStream inputStream = connection.getInputStream();
byte[] bytes = streamToByteArray(inputStream);
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
headers.setContentLength(bytes.length);
headers.setContentDispositionFormData("attachment", fileName);
return new ResponseEntity<>(bytes, headers, HttpStatus.OK);
}
/**
* 功能：将输入流转换成 byte[]
*
* @param is
* @return
* @throws Exception
*/
public static byte[] streamToByteArray(InputStream is) throws Exception {
ByteArrayOutputStream bos = new ByteArrayOutputStream();//创建输出流对象
byte[] b = new byte[1024];
int len;
while ((len = is.read(b)) != -1) {
bos.write(b, 0, len);
}
byte[] array = bos.toByteArray();
bos.close();
return array;
}

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